Modification of the microstructure of thin films by energy beams has been extensively studied. Electron beams and lasers have been used for rapid surface heating. Ion beams at energies of 10 to 10.sup.3 KeV have been widely applied to thin film processing such as surface heating, ion-implantation, and ion mixing.
Recently, ion beams have been used to enhance a number of thermally activated processes, including grain growth of polycrystalline silicon and germanium films, diffusion of gold in amorphous silicon, and epitaxial growth of amorphous silicon on crystalline silicon.
Electrons, being charged particles, interact with the solid strongly. Generation of point defects by high-energy electrons in various semiconductors has been reported. Electron radiation damage on metals and electron induced amorphization of alloys have been studied. However, due to its small mass, the electron is not effective in displacing atoms as ions. The effect of electron irradiation on the microstructure of thin films has not been extensively studied.
Increasingly small structures are required for a variety of microelectronic devices. There are currently no techniques which readily allow fabrication of structures with the desired dimensions for several applications.